Sealed compressor

ABSTRACT

A sealed compressor according to the present invention includes: an electric component ( 110 ) including a stator ( 114 ) and a rotor ( 116 ); a compression component ( 112 ); and a sealed container ( 102 ) configured to accommodate the electric component ( 110 ) and the compression component ( 112 ) and store lubricating oil ( 104 ). The compression component ( 112 ) includes: a shaft ( 118 ) including a main shaft section ( 120 ) and an eccentric shaft section ( 122 ); a cylinder block ( 124 ); a main bearing ( 126 ) provided at the cylinder block ( 124 ) and supporting the main shaft section ( 120 ); and a thrust rolling bearing ( 176 ) provided at a thrust surface ( 160 ) of the main bearing ( 126 ). The thrust rolling bearing ( 176 ) includes: a plurality of rolling elements ( 166 ) held by the cage ( 168 ); an upper race ( 164 ); and a lower race ( 170 ). A ring-shaped, flat, thin plate ( 180 ) is provided between the lower race ( 170 ) and the thrust surface ( 160 ) of the main bearing ( 16 ).

TECHNICAL FIELD

The present invention relates to a sealed compressor used in a refrigeration cycle system, such as a refrigerator-freezer.

BACKGROUND ART

In recent years, regarding a sealed compressor used in a freezer such as a refrigerator-freezer, there is a need for the increase in efficiency for the reduction in power consumption and the reduction in noise. Known is a bearing device used in the sealed compressor for the purpose of increasing the efficiency of the sealed compressor (see PTL 1, for example). Hereinafter, the bearing device disclosed in PTL 1 will be explained in reference to FIGS. 8 and 9.

FIG. 8 is an enlarged view showing a part of the bearing device disclosed in PTL 1. FIG. 9 is a perspective view showing a supporting member of the bearing device shown in FIG. 8. In FIG. 8, an upper-lower direction of the bearing device corresponds to an upper-lower direction of the drawing.

As shown in FIG. 8, in the bearing device disclosed in PTL 1, a radial bearing hub 26 includes an upper tubular extended section 62 which supports an extended section of a crank shaft 20. Then, an axial rolling bearing 76 is attached at an outer side of the upper tubular extended section 62.

The axial rolling bearing 76 includes a circular cage 68 having a plurality of balls 66. The plurality of balls 66 are supported by an upper ring-shaped race 64 and a lower ring-shaped race 70. The upper ring-shaped race 64 is seated on a surface of a peripheral flange 74 of the crank shaft 20. A supporting member 80 is arranged between a lower surface of the lower ring-shaped race 70 and an upper ring-shaped surface 60 of the radial bearing hub 26.

The supporting member 80 is configured to be able to vibrate with respect to the lower ring-shaped race 70 and the upper ring-shaped surface 60 of the radial bearing hub 26. Specifically, the supporting member 80 is formed in an annular shape and includes a pair of main surfaces (an upper surface and a lower surface). A pair of upper contact surfaces 80 a are formed on the upper surface of the supporting member 80 so as to project upward from the upper surface of the supporting member 80, and a pair of lower contact surfaces 80 b are formed on the lower surface of the supporting member 80 so as to project downward from the lower surface of the supporting member 80. The upper contact surface 80 a and the lower contact surface 80 b are formed so as to be displaced from each other by 90 degrees relative to an axial direction of the crank shaft 20.

The supporting member 80 is arranged such that the upper contact surfaces 80 a contact the lower surface of the lower ring-shaped race 70, and the lower contact surfaces 80 b contact the upper ring-shaped surface 60 of the radial bearing hub 26. A space (gap) is formed between a section, opposed to (corresponding to) each upper contact surface 80 a, of the lower surface of the supporting member 80 and the upper ring-shaped surface 60 of the radial bearing hub 26. Similarly, a space (gap) is formed between a section, opposed to (corresponding to) each lower contact surface 80 b, of the upper surface of the supporting member 80 and the lower surface of the lower ring-shaped race 70. To be specific, when viewed from a horizontal direction, the supporting member 80 is formed in a wave shape.

With this, the supporting member 80 can elastically support the axial rolling bearing 76.

CITATION LIST Patent Literature

PTL 1: Published Japanese Translation of PCT Application No. 2005-500476

SUMMARY OF INVENTION Technical Problem

The present inventors have found out that the following problem occurs when a raceway groove formed by a ring-shaped groove is provided at the upper ring-shaped race 64 or the lower ring-shaped race 70 of the bearing device disclosed in PTL 1. To be specific, when forming the raceway groove at the race, waviness is generated at the raceway groove because of accuracy errors. Then, there is a possibility that when the sealed compressor is rotated at high speed at a frequency higher than a commercial power supply frequency, the crank shaft 20 resonates in the upper-lower direction due to excitations caused by the waviness of the raceway groove, and therefore, the noises and vibrations of the compressor increase.

The present invention was made to solve the above conventional problem, and an object of the present invention is to provide a sealed compressor which can avoid resonance of a shaft in an upper-lower direction even when the sealed compressor is rotated at high speed at a frequency higher than a commercial power supply frequency and whose noises and vibrations are reduced.

Solution to Problem

To solve the above conventional problem, a sealed compressor of the present invention includes: an electric component including a stator and a rotor; a compression component driven by the electric component; and a sealed container configured to accommodate the electric component and the compression component and store lubricating oil lubricating the compression component, wherein: the compression component includes a shaft including a main shaft section and an eccentric shaft section, the rotor being fixed to the main shaft section, a cylinder block including a compression chamber, a piston configured to perform a reciprocating movement in the compression chamber, a coupling section coupling the piston and the eccentric shaft section, a main bearing provided at the cylinder block and supporting the main shaft section, and a thrust rolling bearing provided at a thrust surface of the main bearing; the thrust rolling bearing includes an upper race, a lower race, a cage provided between the upper race and the lower race, and a plurality of rolling elements held by the cage; a raceway groove constituted by ring-shaped grooves is provided at opposing main surfaces of the upper and lower races; the rolling elements are arranged at the raceway groove of the upper and lower races; and a ring-shaped, flat, thin plate is provided between the lower race and the thrust surface of the main bearing.

With this, since the lubricating oil gets into gaps between the thrust surface of the main bearing and the thin plate and between the lower race and the thin plate, the resonance of the shaft in the upper-lower direction can be avoided by the damping effect obtained by the lubricating oil films.

Advantageous Effects of Invention

Even when the sealed compressor of the present invention operates at high speed, the resonance of the shaft in the upper-lower direction can be avoided, so that the generation of the noises and the vibrations can be suppressed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a longitudinal sectional view of a sealed compressor according to Embodiment 1.

FIG. 2 is an enlarged schematic diagram showing major sections of the sealed compressor shown in FIG. 1.

FIG. 3 is an enlarged schematic diagram showing major sections of a thrust rolling bearing of the sealed compressor shown in FIG. 1.

FIG. 4 is an enlarged schematic diagram showing major sections of the sealed compressor according to Embodiment 2.

FIG. 5 is an enlarged schematic diagram showing major sections of the sealed compressor according to Embodiment 3.

FIG. 6 is a longitudinal sectional view of the sealed compressor according to Embodiment 4.

FIG. 7 is an enlarged schematic diagram showing major sections of the sealed compressor shown in FIG. 6.

FIG. 8 is an enlarged view showing a part of a bearing device disclosed in PTL 1.

FIG. 9 is a perspective view showing a supporting member of the bearing device shown in FIG. 8.

DESCRIPTION OF EMBODIMENTS

A sealed compressor according to the present invention includes: an electric component including a stator and a rotor; a compression component driven by the electric component; and a sealed container configured to accommodate the electric component and the compression component and store lubricating oil lubricating the compression component, wherein: the compression component includes a shaft including a main shaft section and an eccentric shaft section, the rotor being fixed to the main shaft section, a cylinder block including a compression chamber, a piston configured to perform a reciprocating movement in the compression chamber, a coupling section coupling the piston and the eccentric shaft section, a main bearing provided at the cylinder block and supporting the main shaft section, and a thrust rolling bearing provided at a thrust surface of the main bearing; the thrust rolling bearing includes an upper race, a lower race, a cage provided between the upper race and the lower race, and a plurality of rolling elements held by the cage; a raceway groove constituted by ring-shaped grooves is provided at opposing main surfaces of the upper and lower races; the rolling elements are arranged at the raceway groove of the upper and lower races; and a ring-shaped, flat, thin plate is provided between the lower race and the thrust surface of the main bearing.

The sealed compressor according to the present invention may be configured such that the thin plate is one of a plurality of thin plates provided between the lower race and the thrust surface of the main bearing.

The sealed compressor according to the present invention may be configured such that the thin plate contains at least one metal selected from the group consisting of iron, copper, and aluminum.

The sealed compressor according to the present invention may be configured such that wherein a thickness of the thin plate is not more than one fifth of a thickness of the lower race.

The sealed compressor according to the present invention may be configured such that a thickness of the thin plate is not less than 0.1 mm and not more than 0.2 mm.

The sealed compressor according to the present invention may be configured such that flatness of a main surface, contacting the thrust surface, of the thin plate is lower than flatness of the thrust surface.

The sealed compressor according to the present invention may be configured such that: a flange surface is provided at the shaft so as to be opposed to the other main surface of the upper race; and the thin plate is provided between the flange surface of the shaft and the other main surface of the upper race.

Hereinafter, embodiments of the present invention will be explained in reference to the drawings. In the drawings, the same reference signs are used for the same or corresponding components, and a repetition of the same explanation is avoided. Further, in the drawings, only components necessary to explain the present invention are shown, and the other components may not be shown. Furthermore, the present invention is not limited to the embodiments below.

Embodiment 1 Configuration of Sealed Compressor

FIG. 1 is a longitudinal sectional view of a sealed compressor according to Embodiment 1. FIG. 2 is an enlarged schematic diagram showing major sections of the sealed compressor shown in FIG. 1. FIG. 3 is an enlarged schematic diagram showing major sections of a thrust rolling bearing of the sealed compressor shown in FIG. 1. In FIGS. 1 to 3, an upper-lower direction of the sealed compressor corresponds to an upper-lower direction of each drawing.

As shown in FIGS. 1 to 3, according to a sealed compressor 100 of Embodiment 1, lubricating oil 104 is stored in an inner bottom section of a sealed container 102, and a compressor body 106 is suspended by suspension springs 108 in the sealed container 102.

The sealed container 102 is filled with, for example, R600a (isobutane) that is a cooling medium having a low global warming coefficient.

The compressor body 106 is constituted by an electric component 110 and a compression component 112 driven by the electric component 110. A power supply terminal 113 for supplying electric power to the electric component 110 is attached to the sealed container 102. The power supply terminal 113 is electrically connected through a lead wire 201 to an inverter device 200.

A commercial power supply 203 is electrically connected to the inverter device 200 through an electric wire 202. The inverter device 200 is configured to perform inverter control of the electric power supplied through the power supply terminal 113 to the electric component 110. With this, the electric component 110 drives at a plurality of operation frequencies, and for example, can rotate at high speed at a frequency higher than a commercial power supply frequency.

First, the electric component 110 will be explained. The electric component 110 includes: a stator 114 formed by winding a copper winding wire around an iron core formed by stacking thin plates; and a rotor 116 arranged at an inner diameter side of the stator 114.

Next, the compression component 112 will be explained. In Embodiment 1, the compression component 112 is provided above the electric component 110. The compression component 112 includes a shaft 118, a cylinder block 124, a piston 130, a coupling section (coupling means) 136, and a thrust ball bearing (thrust rolling bearing) 176.

The shaft 118 includes: a main shaft section 120; and an eccentric shaft section 122 having a center axis parallel to a center axis of the main shaft section 120. The main shaft section 120 and the eccentric shaft section 122 are connected to each other by a connecting section 121. The connecting section 121 includes a flange surface 174 substantially perpendicular to the center axis of the main shaft section 120.

The rotor 116 is fixed to the main shaft section 120. The main shaft section 120 and the rotor 116 constitute a shaft assy 118 a. A lower end of the shaft 118 is immersed in the lubricating oil 104. The shaft 118 includes an oiling mechanism 128 constituted by, for example, a spiral groove 128 a formed on a surface of the main shaft section 120.

The cylinder block 124 is provided with a through hole extending in the upper-lower direction, and the through hole constitutes a lubricating oil discharge hole 177. The lubricating oil 104 having been supplied from the oiling mechanism 128 to the shaft 118 and the like is discharged downward through the lubricating oil discharge hole 177.

The cylinder block 124 includes a cylinder 134 that is a cylindrical hole section, and the piston 130 is reciprocatingly inserted into the cylinder 134. The cylinder 134 and the piston 130 form a compression chamber 148. The shaft 118 and the piston 130 are coupled to each other by the coupling section 136. Specifically, a piston pin 138 attached to the piston 130 and the eccentric shaft section 122 are respectively, fittingly inserted into hole sections formed at both ends of the coupling section 136. With this, the eccentric shaft section 122 and the piston 130 are coupled to each other.

A valve plate 146 is attached to an end surface of the cylinder 134. A cylinder head 150 is fixed so as to cover the valve plate 146 like a lid. Further, a suction muffler 152 is arranged between the valve plate 146 and the cylinder head 150. The suction muffler 152 is formed by resin, such as PBT (polybutylene terephthalate), and a silencing space is formed in the suction muffler 152.

The cylinder block 124 includes a main bearing 126 having a cylindrical inner surface. The main shaft section 120 of the shaft 118 is rotatably inserted into and supported by the main bearing 126. The compression component 112 is configured as a cantilever bearing in which the load acting on the eccentric shaft section 122 is supported by the main shaft section 120 and the main bearing 126 arranged under the eccentric shaft section 122.

The thrust ball bearing 176 is interposed between the flange surface 174 of the shaft 118 and the main bearing 126 of the cylinder block 124. With this, the rotation of the shaft 118 becomes smooth by the thrust ball bearing 176. When viewed from below, the flange surface 174 is formed in a substantially circular shape around the main shaft section 120.

Next, the configurations of the shaft 118, the main bearing 126 of the cylinder block 124, and the thrust ball bearing 176 will be explained in more detail in reference to FIGS. 1 to 3.

The connecting section 121 of the shaft 118 is formed in a thick, substantially circular plate shape. The main shaft section 120 is formed on a lower main surface of the connecting section 121 to extend downward from a middle section of the lower main surface of the connecting section 121, and the eccentric shaft section 122 is formed on an upper main surface of the connecting section 121 to extend upward from the vicinity of a peripheral section of the upper main surface of the connecting section 121.

A thrust surface 160 is formed at the main bearing 126 of the cylinder block 124 so as to be substantially perpendicular to a center axis of the main bearing 126. When viewed from the upper-lower direction, the thrust surface 160 is formed in an annular shape. A cylindrical tubular extended section 162 is provided at an inner peripheral section of the thrust surface 160 so as to project upward from the thrust surface 160. An inner peripheral surface of the tubular extended section 162 is formed so as to be opposed to an outer peripheral surface of the main shaft section 120.

The thrust ball bearing 176 includes: an annular upper race 164; a plurality of balls (rolling elements) 166; an annular cage 168 holding the balls 166; and an annular lower race 170. Since the plurality of balls 166 roll in a point contact state, friction is made extremely low. With this, a sliding loss is reduced, and this can improve the efficiency of the compressor.

The members constituting the thrust ball bearing 176 are arranged in order of the lower race 170, the cage 168, and the upper race 164 in a direction from the thrust surface 160 toward the upper side. More specifically, the lower race 170 and the cage 168 are arranged such that the tubular extended section 162 is inserted through center holes thereof. The upper race 164 is located above the tubular extended section 162 and is arranged such that the main shaft section 120 is inserted through a center hole thereof. An axial gap 178 is formed between the tubular extended section 162 and the thrust ball bearing 176.

Each of the upper race 164 and the lower race 170 includes a pair of main surfaces. Ring-shaped grooves are respectively formed on opposing main surfaces (raceway surfaces) of the upper and lower races 164 and 170, and these grooves constitute a raceway groove 179. The raceway groove 179 is formed to have a circular-arc cross-sectional shape similar to the contour shape of the ball 166. The raceway groove 179 is formed by press forging or machine work, and waviness is generated at the raceway groove 179 due to processing accuracy.

The thrust ball bearing 176 is arranged between the flange surface 174 and the thrust surface 160, and an upper surface of the upper race 164 contacts the flange surface 174. A ring-shaped (annular) thin plate 180 including a center hole is provided between a lower surface of the lower race 170 and the thrust surface 160. More specifically, when viewed from the upper-lower direction, the thin plate 180 is provided so as to overlap the center of the revolution orbit of the balls 166.

The thin plate 180 is configured to contain at least one metal selected from the group consisting of iron, copper, and aluminum. For example, the thin plate 180 may be constituted by SPCC (cold rolled steel plate) or a shim ring.

The thin plate 180 may be formed such that the thickness thereof becomes not more than one fifth of the thickness of the lower race 170 or becomes not less than 0.1 mm and not more than 0.2 mm. When the thickness of the thin plate 180 is not less than 0.1 mm, the stiffness can be adequately secured. When the thickness of the thin plate 180 is not more than 0.2 mm, the thin plate 180 can be arranged in the existing sealed compressor 100 without any design change.

In order to suppress the resonance of the shaft 118 in the upper-lower direction, the width size (length that is a half of a difference between the outer diameter and the inner diameter) of the thin plate 180 may be not less than the width size of the raceway groove 179. In order that the thin plate 180 is arranged at the thrust surface 160, the width size of the thin plate 180 may be not more than the width size of the thrust surface 160.

In order that the thin plate 180 is arranged at the thrust surface 160, the thin plate 180 is formed such that the inner diameter thereof is larger than the outer diameter of the tubular extended section 162 and smaller than the outer diameter of the thrust surface 160. In a case where the sealed compressor 100 is configured such that the tubular extended section 162 is not formed at the main bearing 126, the thin plate 180 is formed such that the inner diameter thereof is larger than the outer diameter of the main shaft section 120.

Further, the thin plate 180 is formed such that: the flatness of each of a pair of main surfaces thereof is lower than the flatness of the thrust surface 160; and the main surfaces thereof are substantially parallel to each other. In other words, the pair of main surfaces of the thin plate 180 do not have waviness (deflection) unlike a wave washer. It should be noted that the flatness denotes a minimum interval between two geometrically proper parallel flat surfaces when a target flat surface is sandwiched between these two flat surfaces.

Then, a surface having the flatness of about 50 μm or less by machine work is formed on the thrust surface 160. Therefore, minute gaps 181 are entirely formed between the thrust surface 160 and a lower surface of the thin plate 180. Similarly, minute gaps 182 are entirely formed between the lower surface of the lower race 170 and an upper surface of the thin plate 180. The lubricating oil 104 gets into the gaps 181 and the gaps 182 to form oil films.

Therefore, the lower surface of the thin plate 180 entirely contacts the thrust surface 160 via the oil film, and the upper surface of the thin plate 180 entirely contacts the lower surface of the lower race 170 via the oil film. With this, the entire oil films of the lubricating oil 104 existing in the gaps 181 and the gaps 182 serve as oil dampers.

The oil films formed at the gaps 181 and the gaps 182 are formed in such a manner that when arranging the thin plate 180 and the thrust ball bearing 176 at the main bearing 126 in the process of manufacturing the sealed compressor 100, the lubricating oil 104 is applied to the thin plate 180 and the like.

Operations of Sealed Compressor

Next, operations of the sealed compressor 100 according to Embodiment 1 will be explained in reference to FIGS. 1 to 3.

First, the electric power is supplied from the commercial power supply 203 to the inverter device 200, and the inverter device 200 supplies the electric power to the stator 114 of the electric component 110 through the lead wire 201, the power supply terminal 113, and the like. With this, a magnetic field is generated at the stator 114, and the main shaft section 120 of the shaft 118 fixed to the rotor 116 rotates by the rotation of the rotor 116.

The eccentric rotation of the eccentric shaft section 122 associated with the rotation of the main shaft section 120 is converted by the coupling section 136 to cause the piston 130 to perform a reciprocating movement in the cylinder 134. Then, a compression operation of suctioning the cooling medium of the sealed container 102 into the compression chamber 148 and compressing the cooling medium by the change in the volume of the compression chamber 148 is performed.

In the suction step associated with the compression operation, the cooling medium in the sealed container 102 is intermittently suctioned into the compression chamber 148 through the suction muffler 152 to be compressed in the compression chamber 148. After that, the high-temperature, high-pressure cooling medium flows through an ejection pipe and the like to be supplied from the sealed container 102 to a refrigeration cycle (not shown).

By the rotation of the shaft 118, the lubricating oil 104 is supplied to the main shaft section 120 by the oiling mechanism 128 to lubricate the main shaft section 120. After that, a part of the lubricating oil 104 is supplied through the axial gap 178 to respective members of the compression component 112 to lubricate respective slide sections. Then, the lubricating oil 104 is discharged downward through the lubricating oil discharge hole 177 of the cylinder block 124. Another part of the lubricating oil 104 is supplied through the axial gap 178 to the thrust ball bearing 176. Then, after the lubricating oil 104 supplied to the thrust ball bearing 176 lubricates the thrust surface 160, a part thereof gets into the gaps 181 and the gap 182, and another part thereof is discharged downward through the lubricating oil discharge hole 177.

Operational Advantages of Sealed Compressor

Next, operational advantages of the sealed compressor 100 according to Embodiment 1 will be explained in reference to FIGS. 1 to 3.

The thrust ball bearing 176 is provided at the sealed compressor 100 according to Embodiment 1. Therefore, since the balls 166 roll between the upper race 164 and the lower race 170, the sliding loss of the shaft 118 can be suppressed, and the torque for rotating the shaft 118 can be reduced. With this, the electric power supplied to the electric component 110 can be reduced, and the efficiency of the sealed compressor 100 can be increased.

The loads of the shaft 118, the rotor 116, and the like act on the raceway groove 179 via the upper race 164 and the lower race 170. As described above, the raceway groove 179 has the waviness due to the processing accuracy.

Therefore, while the sealed compressor 100 is operating, the balls 166 on the raceway groove 179 receive excitations caused by the waviness. The excitations become large especially when the sealed compressor equipped with an inverter motor which rotates at high speed operates at high speed and may cause the resonance of the shaft 118 in the upper-lower direction via the upper race 164 and the lower race 170.

However, in the sealed compressor 100 according to Embodiment 1, the thin plate 180 having a flat shape is provided between the lower race 170 and the thrust surface 160. Therefore, the lubricating oil 104 gets into the gaps 181 formed between the thrust surface 160 and the lower surface of the thin plate 180 and the gaps 182 formed between the upper surface of the thin plate 180 and the lower surface of the lower race 170, and the damping effect is generated by the oil films formed entirely. With this, the resonance of the shaft 118 in the upper-lower direction can be avoided by the damping effect, so that the increases in the noises and vibrations of the sealed compressor 100 can be suppressed.

In the bearing device disclosed in PTL 1, the supporting member 80 is arranged between the lower surface of the lower ring-shaped race 70 and the upper ring-shaped surface 60 of the radial bearing hub 26. However, as described above, when viewed from the horizontal direction, the supporting member 80 is formed in a wave shape.

Therefore, a space (gap) is formed between a section, opposed to (corresponding to) each upper contact surface 80 a, of the lower surface of the supporting member 80 and the upper ring-shaped surface 60 of the radial bearing hub 26. Similarly, a space (gap) is formed between a section, opposed to (corresponding to) each lower contact surface 80 b, of the upper surface of the supporting member 80 and the lower surface of the lower ring-shaped race 70. Therefore, since the supporting member 80 point-contacts or line-contacts the upper ring-shaped surface 60 and the lower ring-shaped race 70, the oil films formed at these contact sections are small, so that the damping effect by the oil films is inadequate.

Embodiment 2

The sealed compressor according to Embodiment 2 is configured such that a plurality of thin plates are provided between the lower race and the thrust surface of the main bearing.

Configuration of Sealed Compressor

FIG. 4 is an enlarged schematic diagram showing major sections of the sealed compressor according to Embodiment 2. In FIG. 4, the upper-lower direction of the sealed compressor corresponds to the upper-lower direction of the drawing.

As shown in FIG. 4, the sealed compressor 100 according to Embodiment 2 is the same in basic configuration as the sealed compressor 100 according to Embodiment 1 but is different from the sealed compressor 100 according to Embodiment 1 in that a plurality of (herein, three) thin plates 180 are provided. Specifically, a thin plate 180C, a thin plate 180B, and a thin plate 180A are provided in this order in a direction from the thrust surface 160 toward an upper side.

With this, a gap 184 is formed between the thin plate 180C and the thin plate 180B, and a gap 183 is formed between the thin plate 180B and the thin plate 180A. The lubricating oil 104 gets into the gap 183 and the gap 184.

Therefore, the sealed compressor 100 according to Embodiment 2 generates the damping effect higher than that of the sealed compressor 100 according to Embodiment 1. On this account, the resonance of the shaft 118 in the upper-lower direction can be further avoided, so that the increases in the noises and vibrations of the sealed compressor 100 can be further suppressed.

Embodiment 3

The sealed compressor according to Embodiment 3 is configured such that: a flange surface is provided at the shaft so as to be opposed to the other main surface of the upper race; and the thin plate is provided between the flange surface of the shaft and the other main surface of the upper race.

FIG. 5 is an enlarged schematic diagram showing major sections of the sealed compressor according to Embodiment 3. In FIG. 5, the upper-lower direction of the sealed compressor corresponds to the upper-lower direction of the drawing.

As shown in FIG. 5, the sealed compressor 100 according to Embodiment 3 is the same in basic configuration as the sealed compressor 100 according to Embodiment 1 but is different from the sealed compressor 100 according to Embodiment 1 in that a ring-shaped (annular) thin plate 190 having an inner peripheral surface and an outer peripheral surface is provided between the flange surface 174 of the shaft 118 and the upper surface of the upper race 164.

The thin plate 190 is basically the same in configuration as the thin plate 180 but is different from the thin plate 180 regarding the configurations of the inner peripheral surface and the outer peripheral surface. Specifically, in order not to suppress the rotation of the shaft 118, the thin plate 190 is formed such that the diameter of the inner peripheral surface thereof is larger than the diameter of the outer peripheral surface of the main shaft section 120. The outer peripheral surface of the thin plate 190 may be set arbitrarily as long as the rotation of the shaft 118 is not suppressed.

As with the thrust surface 160, a surface having the flatness of about 50 μm or less by machine work is formed on the flange surface 174 of the shaft 118. Therefore, minute gaps 185 are formed between the flange surface 174 and an upper surface of the thin plate 190. Similarly, minute gaps are formed between a lower surface of the thin plate 190 and an upper surface of the upper race 164 (not shown). The lubricating oil 104 gets in these gaps to form the oil films.

Therefore, the sealed compressor 100 according to Embodiment 3 generates the damping effect higher than that of the sealed compressor 100 according to Embodiment 1. On this account, the resonance of the shaft 118 in the upper-lower direction can be further avoided, so that the increases in the noises and vibrations of the sealed compressor 100 can be further suppressed.

The sealed compressor 100 according to Embodiment 3 adopts a case where one thin plate 190 is provided. However, the sealed compressor 100 according to Embodiment 3 is not limited to this. The sealed compressor 100 according to Embodiment 3 may adopt a case where a plurality of thin plates 190 are provided. Further, the sealed compressor 100 according to Embodiment 3 adopts a case where one thin plate 180 is provided. However, the sealed compressor 100 according to Embodiment 3 is not limited to this. As with the sealed compressor 100 according to Embodiment 2, the sealed compressor 100 according to Embodiment 3 may adopt a case where a plurality of thin plates 180 are provided.

Embodiment 4

FIG. 6 is a longitudinal sectional view of the sealed compressor according to Embodiment 4. FIG. 7 is an enlarged schematic diagram showing major sections of the sealed compressor shown in FIG. 6. In FIGS. 6 and 7, the upper-lower direction of the sealed compressor corresponds to the upper-lower direction of each drawing. In FIG. 6, the inverter device and the like are not shown.

As shown in FIGS. 6 and 7, the sealed compressor 100 according to Embodiment 4 is the same in basic configuration as the sealed compressor 100 according to Embodiment 1 but is different from the sealed compressor 100 according to Embodiment 1 in that: the compression component 112 is arranged under the electric component 110; and the flange surface 174 is provided at the rotor 116. The thrust ball bearing 176 is provided between the flange surface 174 of the rotor 116 and the thrust surface 160 of the main bearing 126.

The sealed compressor 100 according to Embodiment 4 configured as above also has the same operational advantages as the sealed compressor 100 according to Embodiment 1. The sealed compressor 100 according to Embodiment 4 adopts a case where one thin plate 180 is provided. However, the sealed compressor 100 according to Embodiment 4 is not limited to this. As with the sealed compressor 100 according to Embodiment 2, the sealed compressor 100 according to Embodiment 4 may adopt a case where a plurality of thin plates 180 are provided. As with the sealed compressor 100 according to Embodiment 3, the sealed compressor 100 according to Embodiment 4 may adopt a case where the thin plate 190 is provided.

From the foregoing explanation, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Therefore, the foregoing explanation should be interpreted only as an example and is provided for the purpose of teaching the best mode for carrying out the present invention to one skilled in the art. The structures and/or functional details may be substantially modified within the scope of the present invention. In addition, various inventions can be made by suitable combinations of a plurality of components disclosed in the above embodiments.

INDUSTRIAL APPLICABILITY

Even when the sealed compressor according to the present invention operates at high speed, the resonance of the shaft in the upper-lower direction can be avoided, so that the noises and vibrations of the sealed compressor can be suppressed. Thus, the sealed compressor according to the present invention is widely applicable as a sealed compressor used in apparatuses using refrigeration cycles, such as air conditioners and vending machines.

REFERENCE SIGNS LIST

-   -   20 crank shaft     -   26 radial bearing hub     -   60 upper ring-shaped surface     -   62 upper tubular extended section     -   64 upper ring-shaped race     -   66 ball     -   68 circular cage     -   70 lower ring-shaped race     -   74 peripheral flange     -   76 axial rolling bearing     -   80 supporting member     -   80 a upper contact surface     -   80 b lower contact surface     -   100 sealed compressor     -   102 sealed container     -   104 lubricating oil     -   106 compressor body     -   108 suspension spring     -   110 electric component     -   112 compression component     -   113 power supply terminal     -   114 stator     -   116 rotor     -   118 shaft     -   118 a shaft assy     -   120 main shaft section     -   121 connecting section     -   122 eccentric shaft section     -   124 cylinder block     -   126 main bearing     -   128 oiling mechanism     -   128 a groove     -   130 piston     -   134 cylinder     -   136 coupling section     -   138 piston pin     -   146 valve plate     -   148 compression chamber     -   150 cylinder head     -   152 suction muffler     -   160 thrust surface     -   162 tubular extended section     -   164 upper race     -   166 ball     -   168 cage     -   170 lower race     -   174 flange surface     -   176 thrust ball bearing     -   177 lubricating oil discharge hole     -   178 axial gap     -   179 raceway groove     -   180 thin plate     -   180A thin plate     -   180B thin plate     -   180C thin plate     -   181 gap     -   182 gap     -   183 gap     -   184 gap     -   185 gap     -   190 thin plate     -   200 inverter device     -   201 lead wire     -   202 electric wire     -   203 commercial power supply 

1. A sealed compressor comprising: an electric component including a stator and a rotor; a compression component driven by the electric component; and a sealed container configured to accommodate the electric component and the compression component and store lubricating oil lubricating the compression component, wherein: the compression component includes a shaft including a main shaft section and an eccentric shaft section, the rotor being fixed to the main shaft section, a cylinder block including a compression chamber, a piston configured to perform a reciprocating movement in the compression chamber, a coupling section coupling the piston and the eccentric shaft section, a main bearing provided at the cylinder block and supporting the main shaft section, and a thrust rolling bearing provided at a thrust surface of the main bearing; the thrust rolling bearing includes an upper race, a lower race, a cage provided between the upper race and the lower race, and a plurality of rolling elements held by the cage; a raceway groove constituted by ring-shaped grooves is provided at opposing main surfaces of the upper and lower races; the rolling elements are arranged at the raceway groove of the upper and lower races; and a ring-shaped, flat, thin plate is provided between the lower race and the thrust surface of the main bearing.
 2. The sealed compressor according to claim 1, wherein the thin plate is one of a plurality of thin plates provided between the lower race and the thrust surface of the main bearing.
 3. The sealed compressor according to claim 1, wherein the thin plate contains at least one metal selected from the group consisting of iron, copper, and aluminum.
 4. The sealed compressor according to claim 1, wherein a thickness of the thin plate is not more than one fifth of a thickness of the lower race.
 5. The sealed compressor according to claim 1, wherein a thickness of the thin plate is not less than 0.1 mm and not more than 0.2 mm.
 6. The sealed compressor according to claim 1, wherein flatness of a main surface, contacting the thrust surface, of the thin plate is lower than flatness of the thrust surface.
 7. The sealed compressor according to claim 1, wherein: a flange surface is provided at the shaft so as to be opposed to the other main surface of the upper race; and the thin plate is provided between the flange surface of the shaft and the other main surface of the upper race. 